The conservation of biological substances must avoid irreversible cell deterioration which can occur as a result of mechanical or physical action, chemical phenomena and the like. One of the principal approaches to the long-term storage of biological substances, e.g. blood, has been the deep-freezing thereof.
The biological substance, e.g. the blood, can be admixed with a preservative or other protective additive which prevents, during the deep-freezing process, any damage to the cell membrane or hemolysis of the red blood cells of the material.
The blood, admixed with the additive, is then introduced into a container and is agitated in a deep-cooling medium such as liquid nitrogen to freeze the blood which can then be stored for relatively long periods at temperatures below about 200.degree. K.
Notwithstanding the fact that the deep-freezing of blood and the storage of deep-frozen blood at low temperatures has considerably advanced the art of blood storage, the storage time is not unlimited and blood banks or like storage facilities must reckon with a considerable percentage of deterioration of the stored product.